CAJ | 학술논문

采用变步长方法实现非定常Navier-Stokes方程和刚体六自由度运动方程的耦合求解，并对美国ARL旋转弹试验模型的飞行轨迹进行了仿真。旋转弹自由飞行过程中受到空气阻力作用，转速下降，气动力变化趋缓。因此轨迹仿真时先选取较小的时间步长，随着转速的下降逐渐增大步长，这样可以减少计算时间。刚体六自由度运动方程的数值求解采用变步长Adams预估校正法。将定步长和变步长两种方法应用于旋转弹实验模型轨迹仿真，并将计算得到的旋转弹空间位置、姿态角与试验结果进行了对比，结果显示：方法能较精确地仿真旋转弹飞行轨迹。在相同初始步长条件下，变步长方法较定步长方法计算时间减半；在相同计算时间条件下，变步长方法较定步长方法精度更高。
채용변보장방법실현비정상Navier-Stokes방정화강체륙자유도운동방정적우합구해，병대미국ARL선전탄시험모형적비행궤적진행료방진。선전탄자유비행과정중수도공기조력작용，전속하강，기동력변화추완。인차궤적방진시선선취교소적시간보장，수착전속적하강축점증대보장，저양가이감소계산시간。강체륙자유도운동방정적수치구해채용변보장Adams예고교정법。장정보장화변보장량충방법응용우선전탄실험모형궤적방진，병장계산득도적선전탄공간위치、자태각여시험결과진행료대비，결과현시：방법능교정학지방진선전탄비행궤적。재상동초시보장조건하，변보장방법교정보장방법계산시간감반；재상동계산시간조건하，변보장방법교정보장방법정도경고。
The unsteady Navier-Stokes equation and rigid body equations of 6-DOF motion are solved u-sing variable-step coupling computation method to simulate and analyze the flight trajectory of U .S.Army Research Laboratory spinning projectile test model .During the free-flight process ,aerodynamic resistance has significant effect on the projectile motion causing decrease in its revolution which eventually decreases the unsteady aerodynamic load .The initial time step-size of trajectory simulation is chosen small ,which is then gradually increased corresponding with the decreasing revolution .This approach assists in reducing the computational time .The rigid body equations are solved using variable-step Adams prediction-correc-tion method.Both variable-step and fixed-step methods are applied to compute positions ,orientations of the spinning projectile test model .Computed results are found to be generally in good agreement when compared with experiment data .For the same initial step-size , the computational time for the variable-step method is reduced by half of that of the fixed-step method .Also for the same computational time the variable-step method is more accurate .